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1/*
2 * linux/fs/nfs/delegation.c
3 *
4 * Copyright (C) 2004 Trond Myklebust
5 *
6 * NFS file delegation management
7 *
8 */
9#include <linux/completion.h>
10#include <linux/kthread.h>
11#include <linux/module.h>
12#include <linux/sched.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15#include <linux/iversion.h>
16
17#include <linux/nfs4.h>
18#include <linux/nfs_fs.h>
19#include <linux/nfs_xdr.h>
20
21#include "nfs4_fs.h"
22#include "nfs4session.h"
23#include "delegation.h"
24#include "internal.h"
25#include "nfs4trace.h"
26
27static void nfs_free_delegation(struct nfs_delegation *delegation)
28{
29 if (delegation->cred) {
30 put_rpccred(delegation->cred);
31 delegation->cred = NULL;
32 }
33 kfree_rcu(delegation, rcu);
34}
35
36/**
37 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
38 * @delegation: delegation to process
39 *
40 */
41void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
42{
43 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
44}
45
46static bool
47nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
48 fmode_t flags)
49{
50 if (delegation != NULL && (delegation->type & flags) == flags &&
51 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
52 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
53 return true;
54 return false;
55}
56
57static int
58nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
59{
60 struct nfs_delegation *delegation;
61 int ret = 0;
62
63 flags &= FMODE_READ|FMODE_WRITE;
64 rcu_read_lock();
65 delegation = rcu_dereference(NFS_I(inode)->delegation);
66 if (nfs4_is_valid_delegation(delegation, flags)) {
67 if (mark)
68 nfs_mark_delegation_referenced(delegation);
69 ret = 1;
70 }
71 rcu_read_unlock();
72 return ret;
73}
74/**
75 * nfs_have_delegation - check if inode has a delegation, mark it
76 * NFS_DELEGATION_REFERENCED if there is one.
77 * @inode: inode to check
78 * @flags: delegation types to check for
79 *
80 * Returns one if inode has the indicated delegation, otherwise zero.
81 */
82int nfs4_have_delegation(struct inode *inode, fmode_t flags)
83{
84 return nfs4_do_check_delegation(inode, flags, true);
85}
86
87/*
88 * nfs4_check_delegation - check if inode has a delegation, do not mark
89 * NFS_DELEGATION_REFERENCED if it has one.
90 */
91int nfs4_check_delegation(struct inode *inode, fmode_t flags)
92{
93 return nfs4_do_check_delegation(inode, flags, false);
94}
95
96static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
97{
98 struct inode *inode = state->inode;
99 struct file_lock *fl;
100 struct file_lock_context *flctx = inode->i_flctx;
101 struct list_head *list;
102 int status = 0;
103
104 if (flctx == NULL)
105 goto out;
106
107 list = &flctx->flc_posix;
108 spin_lock(&flctx->flc_lock);
109restart:
110 list_for_each_entry(fl, list, fl_list) {
111 if (nfs_file_open_context(fl->fl_file) != ctx)
112 continue;
113 spin_unlock(&flctx->flc_lock);
114 status = nfs4_lock_delegation_recall(fl, state, stateid);
115 if (status < 0)
116 goto out;
117 spin_lock(&flctx->flc_lock);
118 }
119 if (list == &flctx->flc_posix) {
120 list = &flctx->flc_flock;
121 goto restart;
122 }
123 spin_unlock(&flctx->flc_lock);
124out:
125 return status;
126}
127
128static int nfs_delegation_claim_opens(struct inode *inode,
129 const nfs4_stateid *stateid, fmode_t type)
130{
131 struct nfs_inode *nfsi = NFS_I(inode);
132 struct nfs_open_context *ctx;
133 struct nfs4_state_owner *sp;
134 struct nfs4_state *state;
135 unsigned int seq;
136 int err;
137
138again:
139 spin_lock(&inode->i_lock);
140 list_for_each_entry(ctx, &nfsi->open_files, list) {
141 state = ctx->state;
142 if (state == NULL)
143 continue;
144 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
145 continue;
146 if (!nfs4_valid_open_stateid(state))
147 continue;
148 if (!nfs4_stateid_match(&state->stateid, stateid))
149 continue;
150 get_nfs_open_context(ctx);
151 spin_unlock(&inode->i_lock);
152 sp = state->owner;
153 /* Block nfs4_proc_unlck */
154 mutex_lock(&sp->so_delegreturn_mutex);
155 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
156 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
157 if (!err)
158 err = nfs_delegation_claim_locks(ctx, state, stateid);
159 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
160 err = -EAGAIN;
161 mutex_unlock(&sp->so_delegreturn_mutex);
162 put_nfs_open_context(ctx);
163 if (err != 0)
164 return err;
165 goto again;
166 }
167 spin_unlock(&inode->i_lock);
168 return 0;
169}
170
171/**
172 * nfs_inode_reclaim_delegation - process a delegation reclaim request
173 * @inode: inode to process
174 * @cred: credential to use for request
175 * @type: delegation type
176 * @stateid: delegation stateid
177 * @pagemod_limit: write delegation "space_limit"
178 *
179 */
180void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
181 fmode_t type,
182 const nfs4_stateid *stateid,
183 unsigned long pagemod_limit)
184{
185 struct nfs_delegation *delegation;
186 struct rpc_cred *oldcred = NULL;
187
188 rcu_read_lock();
189 delegation = rcu_dereference(NFS_I(inode)->delegation);
190 if (delegation != NULL) {
191 spin_lock(&delegation->lock);
192 if (delegation->inode != NULL) {
193 nfs4_stateid_copy(&delegation->stateid, stateid);
194 delegation->type = type;
195 delegation->pagemod_limit = pagemod_limit;
196 oldcred = delegation->cred;
197 delegation->cred = get_rpccred(cred);
198 clear_bit(NFS_DELEGATION_NEED_RECLAIM,
199 &delegation->flags);
200 spin_unlock(&delegation->lock);
201 rcu_read_unlock();
202 put_rpccred(oldcred);
203 trace_nfs4_reclaim_delegation(inode, type);
204 return;
205 }
206 /* We appear to have raced with a delegation return. */
207 spin_unlock(&delegation->lock);
208 }
209 rcu_read_unlock();
210 nfs_inode_set_delegation(inode, cred, type, stateid, pagemod_limit);
211}
212
213static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
214{
215 int res = 0;
216
217 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
218 res = nfs4_proc_delegreturn(inode,
219 delegation->cred,
220 &delegation->stateid,
221 issync);
222 nfs_free_delegation(delegation);
223 return res;
224}
225
226static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
227{
228 struct inode *inode = NULL;
229
230 spin_lock(&delegation->lock);
231 if (delegation->inode != NULL)
232 inode = igrab(delegation->inode);
233 spin_unlock(&delegation->lock);
234 return inode;
235}
236
237static struct nfs_delegation *
238nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
239{
240 struct nfs_delegation *ret = NULL;
241 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
242
243 if (delegation == NULL)
244 goto out;
245 spin_lock(&delegation->lock);
246 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
247 ret = delegation;
248 spin_unlock(&delegation->lock);
249out:
250 return ret;
251}
252
253static struct nfs_delegation *
254nfs_start_delegation_return(struct nfs_inode *nfsi)
255{
256 struct nfs_delegation *delegation;
257
258 rcu_read_lock();
259 delegation = nfs_start_delegation_return_locked(nfsi);
260 rcu_read_unlock();
261 return delegation;
262}
263
264static void
265nfs_abort_delegation_return(struct nfs_delegation *delegation,
266 struct nfs_client *clp)
267{
268
269 spin_lock(&delegation->lock);
270 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
271 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
272 spin_unlock(&delegation->lock);
273 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
274}
275
276static struct nfs_delegation *
277nfs_detach_delegation_locked(struct nfs_inode *nfsi,
278 struct nfs_delegation *delegation,
279 struct nfs_client *clp)
280{
281 struct nfs_delegation *deleg_cur =
282 rcu_dereference_protected(nfsi->delegation,
283 lockdep_is_held(&clp->cl_lock));
284
285 if (deleg_cur == NULL || delegation != deleg_cur)
286 return NULL;
287
288 spin_lock(&delegation->lock);
289 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
290 list_del_rcu(&delegation->super_list);
291 delegation->inode = NULL;
292 rcu_assign_pointer(nfsi->delegation, NULL);
293 spin_unlock(&delegation->lock);
294 return delegation;
295}
296
297static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
298 struct nfs_delegation *delegation,
299 struct nfs_server *server)
300{
301 struct nfs_client *clp = server->nfs_client;
302
303 spin_lock(&clp->cl_lock);
304 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
305 spin_unlock(&clp->cl_lock);
306 return delegation;
307}
308
309static struct nfs_delegation *
310nfs_inode_detach_delegation(struct inode *inode)
311{
312 struct nfs_inode *nfsi = NFS_I(inode);
313 struct nfs_server *server = NFS_SERVER(inode);
314 struct nfs_delegation *delegation;
315
316 delegation = nfs_start_delegation_return(nfsi);
317 if (delegation == NULL)
318 return NULL;
319 return nfs_detach_delegation(nfsi, delegation, server);
320}
321
322static void
323nfs_update_inplace_delegation(struct nfs_delegation *delegation,
324 const struct nfs_delegation *update)
325{
326 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
327 delegation->stateid.seqid = update->stateid.seqid;
328 smp_wmb();
329 delegation->type = update->type;
330 }
331}
332
333/**
334 * nfs_inode_set_delegation - set up a delegation on an inode
335 * @inode: inode to which delegation applies
336 * @cred: cred to use for subsequent delegation processing
337 * @type: delegation type
338 * @stateid: delegation stateid
339 * @pagemod_limit: write delegation "space_limit"
340 *
341 * Returns zero on success, or a negative errno value.
342 */
343int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred,
344 fmode_t type,
345 const nfs4_stateid *stateid,
346 unsigned long pagemod_limit)
347{
348 struct nfs_server *server = NFS_SERVER(inode);
349 struct nfs_client *clp = server->nfs_client;
350 struct nfs_inode *nfsi = NFS_I(inode);
351 struct nfs_delegation *delegation, *old_delegation;
352 struct nfs_delegation *freeme = NULL;
353 int status = 0;
354
355 delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
356 if (delegation == NULL)
357 return -ENOMEM;
358 nfs4_stateid_copy(&delegation->stateid, stateid);
359 delegation->type = type;
360 delegation->pagemod_limit = pagemod_limit;
361 delegation->change_attr = inode_peek_iversion_raw(inode);
362 delegation->cred = get_rpccred(cred);
363 delegation->inode = inode;
364 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
365 spin_lock_init(&delegation->lock);
366
367 spin_lock(&clp->cl_lock);
368 old_delegation = rcu_dereference_protected(nfsi->delegation,
369 lockdep_is_held(&clp->cl_lock));
370 if (old_delegation != NULL) {
371 /* Is this an update of the existing delegation? */
372 if (nfs4_stateid_match_other(&old_delegation->stateid,
373 &delegation->stateid)) {
374 nfs_update_inplace_delegation(old_delegation,
375 delegation);
376 goto out;
377 }
378 /*
379 * Deal with broken servers that hand out two
380 * delegations for the same file.
381 * Allow for upgrades to a WRITE delegation, but
382 * nothing else.
383 */
384 dfprintk(FILE, "%s: server %s handed out "
385 "a duplicate delegation!\n",
386 __func__, clp->cl_hostname);
387 if (delegation->type == old_delegation->type ||
388 !(delegation->type & FMODE_WRITE)) {
389 freeme = delegation;
390 delegation = NULL;
391 goto out;
392 }
393 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
394 &old_delegation->flags))
395 goto out;
396 freeme = nfs_detach_delegation_locked(nfsi,
397 old_delegation, clp);
398 if (freeme == NULL)
399 goto out;
400 }
401 list_add_tail_rcu(&delegation->super_list, &server->delegations);
402 rcu_assign_pointer(nfsi->delegation, delegation);
403 delegation = NULL;
404
405 trace_nfs4_set_delegation(inode, type);
406
407out:
408 spin_unlock(&clp->cl_lock);
409 if (delegation != NULL)
410 nfs_free_delegation(delegation);
411 if (freeme != NULL)
412 nfs_do_return_delegation(inode, freeme, 0);
413 return status;
414}
415
416/*
417 * Basic procedure for returning a delegation to the server
418 */
419static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
420{
421 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
422 struct nfs_inode *nfsi = NFS_I(inode);
423 int err = 0;
424
425 if (delegation == NULL)
426 return 0;
427 do {
428 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
429 break;
430 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
431 delegation->type);
432 if (!issync || err != -EAGAIN)
433 break;
434 /*
435 * Guard against state recovery
436 */
437 err = nfs4_wait_clnt_recover(clp);
438 } while (err == 0);
439
440 if (err) {
441 nfs_abort_delegation_return(delegation, clp);
442 goto out;
443 }
444 if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
445 goto out;
446
447 err = nfs_do_return_delegation(inode, delegation, issync);
448out:
449 return err;
450}
451
452static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
453{
454 bool ret = false;
455
456 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
457 goto out;
458 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
459 ret = true;
460 if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
461 struct inode *inode;
462
463 spin_lock(&delegation->lock);
464 inode = delegation->inode;
465 if (inode && list_empty(&NFS_I(inode)->open_files))
466 ret = true;
467 spin_unlock(&delegation->lock);
468 }
469out:
470 return ret;
471}
472
473/**
474 * nfs_client_return_marked_delegations - return previously marked delegations
475 * @clp: nfs_client to process
476 *
477 * Note that this function is designed to be called by the state
478 * manager thread. For this reason, it cannot flush the dirty data,
479 * since that could deadlock in case of a state recovery error.
480 *
481 * Returns zero on success, or a negative errno value.
482 */
483int nfs_client_return_marked_delegations(struct nfs_client *clp)
484{
485 struct nfs_delegation *delegation;
486 struct nfs_server *server;
487 struct inode *inode;
488 int err = 0;
489
490restart:
491 rcu_read_lock();
492 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
493 list_for_each_entry_rcu(delegation, &server->delegations,
494 super_list) {
495 if (!nfs_delegation_need_return(delegation))
496 continue;
497 if (!nfs_sb_active(server->super))
498 continue;
499 inode = nfs_delegation_grab_inode(delegation);
500 if (inode == NULL) {
501 rcu_read_unlock();
502 nfs_sb_deactive(server->super);
503 goto restart;
504 }
505 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
506 rcu_read_unlock();
507
508 err = nfs_end_delegation_return(inode, delegation, 0);
509 iput(inode);
510 nfs_sb_deactive(server->super);
511 if (!err)
512 goto restart;
513 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
514 return err;
515 }
516 }
517 rcu_read_unlock();
518 return 0;
519}
520
521/**
522 * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
523 * @inode: inode to process
524 *
525 * Does not protect against delegation reclaims, therefore really only safe
526 * to be called from nfs4_clear_inode().
527 */
528void nfs_inode_return_delegation_noreclaim(struct inode *inode)
529{
530 struct nfs_delegation *delegation;
531
532 delegation = nfs_inode_detach_delegation(inode);
533 if (delegation != NULL)
534 nfs_do_return_delegation(inode, delegation, 1);
535}
536
537/**
538 * nfs_inode_return_delegation - synchronously return a delegation
539 * @inode: inode to process
540 *
541 * This routine will always flush any dirty data to disk on the
542 * assumption that if we need to return the delegation, then
543 * we should stop caching.
544 *
545 * Returns zero on success, or a negative errno value.
546 */
547int nfs4_inode_return_delegation(struct inode *inode)
548{
549 struct nfs_inode *nfsi = NFS_I(inode);
550 struct nfs_delegation *delegation;
551 int err = 0;
552
553 nfs_wb_all(inode);
554 delegation = nfs_start_delegation_return(nfsi);
555 if (delegation != NULL)
556 err = nfs_end_delegation_return(inode, delegation, 1);
557 return err;
558}
559
560/**
561 * nfs4_inode_make_writeable
562 * @inode: pointer to inode
563 *
564 * Make the inode writeable by returning the delegation if necessary
565 *
566 * Returns zero on success, or a negative errno value.
567 */
568int nfs4_inode_make_writeable(struct inode *inode)
569{
570 if (!nfs4_has_session(NFS_SERVER(inode)->nfs_client) ||
571 !nfs4_check_delegation(inode, FMODE_WRITE))
572 return nfs4_inode_return_delegation(inode);
573 return 0;
574}
575
576static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
577 struct nfs_delegation *delegation)
578{
579 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
580 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
581}
582
583static void nfs_mark_return_delegation(struct nfs_server *server,
584 struct nfs_delegation *delegation)
585{
586 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
587 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
588}
589
590static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
591{
592 struct nfs_delegation *delegation;
593 bool ret = false;
594
595 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
596 nfs_mark_return_delegation(server, delegation);
597 ret = true;
598 }
599 return ret;
600}
601
602static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
603{
604 struct nfs_server *server;
605
606 rcu_read_lock();
607 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
608 nfs_server_mark_return_all_delegations(server);
609 rcu_read_unlock();
610}
611
612static void nfs_delegation_run_state_manager(struct nfs_client *clp)
613{
614 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
615 nfs4_schedule_state_manager(clp);
616}
617
618/**
619 * nfs_expire_all_delegations
620 * @clp: client to process
621 *
622 */
623void nfs_expire_all_delegations(struct nfs_client *clp)
624{
625 nfs_client_mark_return_all_delegations(clp);
626 nfs_delegation_run_state_manager(clp);
627}
628
629/**
630 * nfs_super_return_all_delegations - return delegations for one superblock
631 * @sb: sb to process
632 *
633 */
634void nfs_server_return_all_delegations(struct nfs_server *server)
635{
636 struct nfs_client *clp = server->nfs_client;
637 bool need_wait;
638
639 if (clp == NULL)
640 return;
641
642 rcu_read_lock();
643 need_wait = nfs_server_mark_return_all_delegations(server);
644 rcu_read_unlock();
645
646 if (need_wait) {
647 nfs4_schedule_state_manager(clp);
648 nfs4_wait_clnt_recover(clp);
649 }
650}
651
652static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
653 fmode_t flags)
654{
655 struct nfs_delegation *delegation;
656
657 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
658 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
659 continue;
660 if (delegation->type & flags)
661 nfs_mark_return_if_closed_delegation(server, delegation);
662 }
663}
664
665static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
666 fmode_t flags)
667{
668 struct nfs_server *server;
669
670 rcu_read_lock();
671 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
672 nfs_mark_return_unused_delegation_types(server, flags);
673 rcu_read_unlock();
674}
675
676static void nfs_mark_delegation_revoked(struct nfs_server *server,
677 struct nfs_delegation *delegation)
678{
679 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
680 delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
681 nfs_mark_return_delegation(server, delegation);
682}
683
684static bool nfs_revoke_delegation(struct inode *inode,
685 const nfs4_stateid *stateid)
686{
687 struct nfs_delegation *delegation;
688 nfs4_stateid tmp;
689 bool ret = false;
690
691 rcu_read_lock();
692 delegation = rcu_dereference(NFS_I(inode)->delegation);
693 if (delegation == NULL)
694 goto out;
695 if (stateid == NULL) {
696 nfs4_stateid_copy(&tmp, &delegation->stateid);
697 stateid = &tmp;
698 } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
699 goto out;
700 nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
701 ret = true;
702out:
703 rcu_read_unlock();
704 if (ret)
705 nfs_inode_find_state_and_recover(inode, stateid);
706 return ret;
707}
708
709void nfs_remove_bad_delegation(struct inode *inode,
710 const nfs4_stateid *stateid)
711{
712 struct nfs_delegation *delegation;
713
714 if (!nfs_revoke_delegation(inode, stateid))
715 return;
716 delegation = nfs_inode_detach_delegation(inode);
717 if (delegation)
718 nfs_free_delegation(delegation);
719}
720EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
721
722/**
723 * nfs_expire_unused_delegation_types
724 * @clp: client to process
725 * @flags: delegation types to expire
726 *
727 */
728void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
729{
730 nfs_client_mark_return_unused_delegation_types(clp, flags);
731 nfs_delegation_run_state_manager(clp);
732}
733
734static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
735{
736 struct nfs_delegation *delegation;
737
738 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
739 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
740 continue;
741 nfs_mark_return_if_closed_delegation(server, delegation);
742 }
743}
744
745/**
746 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
747 * @clp: nfs_client to process
748 *
749 */
750void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
751{
752 struct nfs_server *server;
753
754 rcu_read_lock();
755 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
756 nfs_mark_return_unreferenced_delegations(server);
757 rcu_read_unlock();
758
759 nfs_delegation_run_state_manager(clp);
760}
761
762/**
763 * nfs_async_inode_return_delegation - asynchronously return a delegation
764 * @inode: inode to process
765 * @stateid: state ID information
766 *
767 * Returns zero on success, or a negative errno value.
768 */
769int nfs_async_inode_return_delegation(struct inode *inode,
770 const nfs4_stateid *stateid)
771{
772 struct nfs_server *server = NFS_SERVER(inode);
773 struct nfs_client *clp = server->nfs_client;
774 struct nfs_delegation *delegation;
775
776 rcu_read_lock();
777 delegation = rcu_dereference(NFS_I(inode)->delegation);
778 if (delegation == NULL)
779 goto out_enoent;
780 if (stateid != NULL &&
781 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
782 goto out_enoent;
783 nfs_mark_return_delegation(server, delegation);
784 rcu_read_unlock();
785
786 nfs_delegation_run_state_manager(clp);
787 return 0;
788out_enoent:
789 rcu_read_unlock();
790 return -ENOENT;
791}
792
793static struct inode *
794nfs_delegation_find_inode_server(struct nfs_server *server,
795 const struct nfs_fh *fhandle)
796{
797 struct nfs_delegation *delegation;
798 struct inode *res = NULL;
799
800 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
801 spin_lock(&delegation->lock);
802 if (delegation->inode != NULL &&
803 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
804 res = igrab(delegation->inode);
805 }
806 spin_unlock(&delegation->lock);
807 if (res != NULL)
808 break;
809 }
810 return res;
811}
812
813/**
814 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
815 * @clp: client state handle
816 * @fhandle: filehandle from a delegation recall
817 *
818 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
819 * cannot be found.
820 */
821struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
822 const struct nfs_fh *fhandle)
823{
824 struct nfs_server *server;
825 struct inode *res = NULL;
826
827 rcu_read_lock();
828 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
829 res = nfs_delegation_find_inode_server(server, fhandle);
830 if (res != NULL)
831 break;
832 }
833 rcu_read_unlock();
834 return res;
835}
836
837static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
838{
839 struct nfs_delegation *delegation;
840
841 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
842 /*
843 * If the delegation may have been admin revoked, then we
844 * cannot reclaim it.
845 */
846 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
847 continue;
848 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
849 }
850}
851
852/**
853 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
854 * @clp: nfs_client to process
855 *
856 */
857void nfs_delegation_mark_reclaim(struct nfs_client *clp)
858{
859 struct nfs_server *server;
860
861 rcu_read_lock();
862 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
863 nfs_delegation_mark_reclaim_server(server);
864 rcu_read_unlock();
865}
866
867/**
868 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
869 * @clp: nfs_client to process
870 *
871 */
872void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
873{
874 struct nfs_delegation *delegation;
875 struct nfs_server *server;
876 struct inode *inode;
877
878restart:
879 rcu_read_lock();
880 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
881 list_for_each_entry_rcu(delegation, &server->delegations,
882 super_list) {
883 if (test_bit(NFS_DELEGATION_RETURNING,
884 &delegation->flags))
885 continue;
886 if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
887 &delegation->flags) == 0)
888 continue;
889 if (!nfs_sb_active(server->super))
890 continue;
891 inode = nfs_delegation_grab_inode(delegation);
892 if (inode == NULL) {
893 rcu_read_unlock();
894 nfs_sb_deactive(server->super);
895 goto restart;
896 }
897 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
898 rcu_read_unlock();
899 if (delegation != NULL) {
900 delegation = nfs_detach_delegation(NFS_I(inode),
901 delegation, server);
902 if (delegation != NULL)
903 nfs_free_delegation(delegation);
904 }
905 iput(inode);
906 nfs_sb_deactive(server->super);
907 goto restart;
908 }
909 }
910 rcu_read_unlock();
911}
912
913static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
914{
915 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
916 BIT(NFS4CLNT_LEASE_EXPIRED) |
917 BIT(NFS4CLNT_SESSION_RESET))) != 0;
918}
919
920static void nfs_mark_test_expired_delegation(struct nfs_server *server,
921 struct nfs_delegation *delegation)
922{
923 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
924 return;
925 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
926 set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
927 set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
928}
929
930static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
931 struct inode *inode)
932{
933 struct nfs_delegation *delegation;
934
935 rcu_read_lock();
936 delegation = rcu_dereference(NFS_I(inode)->delegation);
937 if (delegation)
938 nfs_mark_test_expired_delegation(server, delegation);
939 rcu_read_unlock();
940
941}
942
943static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
944{
945 struct nfs_delegation *delegation;
946
947 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
948 nfs_mark_test_expired_delegation(server, delegation);
949}
950
951/**
952 * nfs_mark_test_expired_all_delegations - mark all delegations for testing
953 * @clp: nfs_client to process
954 *
955 * Iterates through all the delegations associated with this server and
956 * marks them as needing to be checked for validity.
957 */
958void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
959{
960 struct nfs_server *server;
961
962 rcu_read_lock();
963 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
964 nfs_delegation_mark_test_expired_server(server);
965 rcu_read_unlock();
966}
967
968/**
969 * nfs_reap_expired_delegations - reap expired delegations
970 * @clp: nfs_client to process
971 *
972 * Iterates through all the delegations associated with this server and
973 * checks if they have may have been revoked. This function is usually
974 * expected to be called in cases where the server may have lost its
975 * lease.
976 */
977void nfs_reap_expired_delegations(struct nfs_client *clp)
978{
979 const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
980 struct nfs_delegation *delegation;
981 struct nfs_server *server;
982 struct inode *inode;
983 struct rpc_cred *cred;
984 nfs4_stateid stateid;
985
986restart:
987 rcu_read_lock();
988 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
989 list_for_each_entry_rcu(delegation, &server->delegations,
990 super_list) {
991 if (test_bit(NFS_DELEGATION_RETURNING,
992 &delegation->flags))
993 continue;
994 if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
995 &delegation->flags) == 0)
996 continue;
997 if (!nfs_sb_active(server->super))
998 continue;
999 inode = nfs_delegation_grab_inode(delegation);
1000 if (inode == NULL) {
1001 rcu_read_unlock();
1002 nfs_sb_deactive(server->super);
1003 goto restart;
1004 }
1005 cred = get_rpccred_rcu(delegation->cred);
1006 nfs4_stateid_copy(&stateid, &delegation->stateid);
1007 clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
1008 rcu_read_unlock();
1009 if (cred != NULL &&
1010 ops->test_and_free_expired(server, &stateid, cred) < 0) {
1011 nfs_revoke_delegation(inode, &stateid);
1012 nfs_inode_find_state_and_recover(inode, &stateid);
1013 }
1014 put_rpccred(cred);
1015 if (nfs4_server_rebooted(clp)) {
1016 nfs_inode_mark_test_expired_delegation(server,inode);
1017 iput(inode);
1018 nfs_sb_deactive(server->super);
1019 return;
1020 }
1021 iput(inode);
1022 nfs_sb_deactive(server->super);
1023 goto restart;
1024 }
1025 }
1026 rcu_read_unlock();
1027}
1028
1029void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1030 const nfs4_stateid *stateid)
1031{
1032 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1033 struct nfs_delegation *delegation;
1034 bool found = false;
1035
1036 rcu_read_lock();
1037 delegation = rcu_dereference(NFS_I(inode)->delegation);
1038 if (delegation &&
1039 nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1040 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1041 found = true;
1042 }
1043 rcu_read_unlock();
1044 if (found)
1045 nfs4_schedule_state_manager(clp);
1046}
1047
1048/**
1049 * nfs_delegations_present - check for existence of delegations
1050 * @clp: client state handle
1051 *
1052 * Returns one if there are any nfs_delegation structures attached
1053 * to this nfs_client.
1054 */
1055int nfs_delegations_present(struct nfs_client *clp)
1056{
1057 struct nfs_server *server;
1058 int ret = 0;
1059
1060 rcu_read_lock();
1061 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1062 if (!list_empty(&server->delegations)) {
1063 ret = 1;
1064 break;
1065 }
1066 rcu_read_unlock();
1067 return ret;
1068}
1069
1070/**
1071 * nfs4_refresh_delegation_stateid - Update delegation stateid seqid
1072 * @dst: stateid to refresh
1073 * @inode: inode to check
1074 *
1075 * Returns "true" and updates "dst->seqid" * if inode had a delegation
1076 * that matches our delegation stateid. Otherwise "false" is returned.
1077 */
1078bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
1079{
1080 struct nfs_delegation *delegation;
1081 bool ret = false;
1082 if (!inode)
1083 goto out;
1084
1085 rcu_read_lock();
1086 delegation = rcu_dereference(NFS_I(inode)->delegation);
1087 if (delegation != NULL &&
1088 nfs4_stateid_match_other(dst, &delegation->stateid)) {
1089 dst->seqid = delegation->stateid.seqid;
1090 return ret;
1091 }
1092 rcu_read_unlock();
1093out:
1094 return ret;
1095}
1096
1097/**
1098 * nfs4_copy_delegation_stateid - Copy inode's state ID information
1099 * @inode: inode to check
1100 * @flags: delegation type requirement
1101 * @dst: stateid data structure to fill in
1102 * @cred: optional argument to retrieve credential
1103 *
1104 * Returns "true" and fills in "dst->data" * if inode had a delegation,
1105 * otherwise "false" is returned.
1106 */
1107bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1108 nfs4_stateid *dst, struct rpc_cred **cred)
1109{
1110 struct nfs_inode *nfsi = NFS_I(inode);
1111 struct nfs_delegation *delegation;
1112 bool ret;
1113
1114 flags &= FMODE_READ|FMODE_WRITE;
1115 rcu_read_lock();
1116 delegation = rcu_dereference(nfsi->delegation);
1117 ret = nfs4_is_valid_delegation(delegation, flags);
1118 if (ret) {
1119 nfs4_stateid_copy(dst, &delegation->stateid);
1120 nfs_mark_delegation_referenced(delegation);
1121 if (cred)
1122 *cred = get_rpccred(delegation->cred);
1123 }
1124 rcu_read_unlock();
1125 return ret;
1126}
1127
1128/**
1129 * nfs4_delegation_flush_on_close - Check if we must flush file on close
1130 * @inode: inode to check
1131 *
1132 * This function checks the number of outstanding writes to the file
1133 * against the delegation 'space_limit' field to see if
1134 * the spec requires us to flush the file on close.
1135 */
1136bool nfs4_delegation_flush_on_close(const struct inode *inode)
1137{
1138 struct nfs_inode *nfsi = NFS_I(inode);
1139 struct nfs_delegation *delegation;
1140 bool ret = true;
1141
1142 rcu_read_lock();
1143 delegation = rcu_dereference(nfsi->delegation);
1144 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1145 goto out;
1146 if (atomic_long_read(&nfsi->nrequests) < delegation->pagemod_limit)
1147 ret = false;
1148out:
1149 rcu_read_unlock();
1150 return ret;
1151}
1/*
2 * linux/fs/nfs/delegation.c
3 *
4 * Copyright (C) 2004 Trond Myklebust
5 *
6 * NFS file delegation management
7 *
8 */
9#include <linux/completion.h>
10#include <linux/kthread.h>
11#include <linux/module.h>
12#include <linux/sched.h>
13#include <linux/slab.h>
14#include <linux/spinlock.h>
15
16#include <linux/nfs4.h>
17#include <linux/nfs_fs.h>
18#include <linux/nfs_xdr.h>
19
20#include "nfs4_fs.h"
21#include "delegation.h"
22#include "internal.h"
23#include "nfs4trace.h"
24
25static void nfs_free_delegation(struct nfs_delegation *delegation)
26{
27 if (delegation->cred) {
28 put_rpccred(delegation->cred);
29 delegation->cred = NULL;
30 }
31 kfree_rcu(delegation, rcu);
32}
33
34/**
35 * nfs_mark_delegation_referenced - set delegation's REFERENCED flag
36 * @delegation: delegation to process
37 *
38 */
39void nfs_mark_delegation_referenced(struct nfs_delegation *delegation)
40{
41 set_bit(NFS_DELEGATION_REFERENCED, &delegation->flags);
42}
43
44static bool
45nfs4_is_valid_delegation(const struct nfs_delegation *delegation,
46 fmode_t flags)
47{
48 if (delegation != NULL && (delegation->type & flags) == flags &&
49 !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) &&
50 !test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
51 return true;
52 return false;
53}
54
55static int
56nfs4_do_check_delegation(struct inode *inode, fmode_t flags, bool mark)
57{
58 struct nfs_delegation *delegation;
59 int ret = 0;
60
61 flags &= FMODE_READ|FMODE_WRITE;
62 rcu_read_lock();
63 delegation = rcu_dereference(NFS_I(inode)->delegation);
64 if (nfs4_is_valid_delegation(delegation, flags)) {
65 if (mark)
66 nfs_mark_delegation_referenced(delegation);
67 ret = 1;
68 }
69 rcu_read_unlock();
70 return ret;
71}
72/**
73 * nfs_have_delegation - check if inode has a delegation, mark it
74 * NFS_DELEGATION_REFERENCED if there is one.
75 * @inode: inode to check
76 * @flags: delegation types to check for
77 *
78 * Returns one if inode has the indicated delegation, otherwise zero.
79 */
80int nfs4_have_delegation(struct inode *inode, fmode_t flags)
81{
82 return nfs4_do_check_delegation(inode, flags, true);
83}
84
85/*
86 * nfs4_check_delegation - check if inode has a delegation, do not mark
87 * NFS_DELEGATION_REFERENCED if it has one.
88 */
89int nfs4_check_delegation(struct inode *inode, fmode_t flags)
90{
91 return nfs4_do_check_delegation(inode, flags, false);
92}
93
94static int nfs_delegation_claim_locks(struct nfs_open_context *ctx, struct nfs4_state *state, const nfs4_stateid *stateid)
95{
96 struct inode *inode = state->inode;
97 struct file_lock *fl;
98 struct file_lock_context *flctx = inode->i_flctx;
99 struct list_head *list;
100 int status = 0;
101
102 if (flctx == NULL)
103 goto out;
104
105 list = &flctx->flc_posix;
106 spin_lock(&flctx->flc_lock);
107restart:
108 list_for_each_entry(fl, list, fl_list) {
109 if (nfs_file_open_context(fl->fl_file) != ctx)
110 continue;
111 spin_unlock(&flctx->flc_lock);
112 status = nfs4_lock_delegation_recall(fl, state, stateid);
113 if (status < 0)
114 goto out;
115 spin_lock(&flctx->flc_lock);
116 }
117 if (list == &flctx->flc_posix) {
118 list = &flctx->flc_flock;
119 goto restart;
120 }
121 spin_unlock(&flctx->flc_lock);
122out:
123 return status;
124}
125
126static int nfs_delegation_claim_opens(struct inode *inode,
127 const nfs4_stateid *stateid, fmode_t type)
128{
129 struct nfs_inode *nfsi = NFS_I(inode);
130 struct nfs_open_context *ctx;
131 struct nfs4_state_owner *sp;
132 struct nfs4_state *state;
133 unsigned int seq;
134 int err;
135
136again:
137 spin_lock(&inode->i_lock);
138 list_for_each_entry(ctx, &nfsi->open_files, list) {
139 state = ctx->state;
140 if (state == NULL)
141 continue;
142 if (!test_bit(NFS_DELEGATED_STATE, &state->flags))
143 continue;
144 if (!nfs4_valid_open_stateid(state))
145 continue;
146 if (!nfs4_stateid_match(&state->stateid, stateid))
147 continue;
148 get_nfs_open_context(ctx);
149 spin_unlock(&inode->i_lock);
150 sp = state->owner;
151 /* Block nfs4_proc_unlck */
152 mutex_lock(&sp->so_delegreturn_mutex);
153 seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
154 err = nfs4_open_delegation_recall(ctx, state, stateid, type);
155 if (!err)
156 err = nfs_delegation_claim_locks(ctx, state, stateid);
157 if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
158 err = -EAGAIN;
159 mutex_unlock(&sp->so_delegreturn_mutex);
160 put_nfs_open_context(ctx);
161 if (err != 0)
162 return err;
163 goto again;
164 }
165 spin_unlock(&inode->i_lock);
166 return 0;
167}
168
169/**
170 * nfs_inode_reclaim_delegation - process a delegation reclaim request
171 * @inode: inode to process
172 * @cred: credential to use for request
173 * @res: new delegation state from server
174 *
175 */
176void nfs_inode_reclaim_delegation(struct inode *inode, struct rpc_cred *cred,
177 struct nfs_openres *res)
178{
179 struct nfs_delegation *delegation;
180 struct rpc_cred *oldcred = NULL;
181
182 rcu_read_lock();
183 delegation = rcu_dereference(NFS_I(inode)->delegation);
184 if (delegation != NULL) {
185 spin_lock(&delegation->lock);
186 if (delegation->inode != NULL) {
187 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
188 delegation->type = res->delegation_type;
189 delegation->pagemod_limit = res->pagemod_limit;
190 oldcred = delegation->cred;
191 delegation->cred = get_rpccred(cred);
192 clear_bit(NFS_DELEGATION_NEED_RECLAIM,
193 &delegation->flags);
194 spin_unlock(&delegation->lock);
195 rcu_read_unlock();
196 put_rpccred(oldcred);
197 trace_nfs4_reclaim_delegation(inode, res->delegation_type);
198 return;
199 }
200 /* We appear to have raced with a delegation return. */
201 spin_unlock(&delegation->lock);
202 }
203 rcu_read_unlock();
204 nfs_inode_set_delegation(inode, cred, res);
205}
206
207static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation *delegation, int issync)
208{
209 int res = 0;
210
211 if (!test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
212 res = nfs4_proc_delegreturn(inode,
213 delegation->cred,
214 &delegation->stateid,
215 issync);
216 nfs_free_delegation(delegation);
217 return res;
218}
219
220static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation)
221{
222 struct inode *inode = NULL;
223
224 spin_lock(&delegation->lock);
225 if (delegation->inode != NULL)
226 inode = igrab(delegation->inode);
227 spin_unlock(&delegation->lock);
228 return inode;
229}
230
231static struct nfs_delegation *
232nfs_start_delegation_return_locked(struct nfs_inode *nfsi)
233{
234 struct nfs_delegation *ret = NULL;
235 struct nfs_delegation *delegation = rcu_dereference(nfsi->delegation);
236
237 if (delegation == NULL)
238 goto out;
239 spin_lock(&delegation->lock);
240 if (!test_and_set_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
241 ret = delegation;
242 spin_unlock(&delegation->lock);
243out:
244 return ret;
245}
246
247static struct nfs_delegation *
248nfs_start_delegation_return(struct nfs_inode *nfsi)
249{
250 struct nfs_delegation *delegation;
251
252 rcu_read_lock();
253 delegation = nfs_start_delegation_return_locked(nfsi);
254 rcu_read_unlock();
255 return delegation;
256}
257
258static void
259nfs_abort_delegation_return(struct nfs_delegation *delegation,
260 struct nfs_client *clp)
261{
262
263 spin_lock(&delegation->lock);
264 clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
265 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
266 spin_unlock(&delegation->lock);
267 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
268}
269
270static struct nfs_delegation *
271nfs_detach_delegation_locked(struct nfs_inode *nfsi,
272 struct nfs_delegation *delegation,
273 struct nfs_client *clp)
274{
275 struct nfs_delegation *deleg_cur =
276 rcu_dereference_protected(nfsi->delegation,
277 lockdep_is_held(&clp->cl_lock));
278
279 if (deleg_cur == NULL || delegation != deleg_cur)
280 return NULL;
281
282 spin_lock(&delegation->lock);
283 set_bit(NFS_DELEGATION_RETURNING, &delegation->flags);
284 list_del_rcu(&delegation->super_list);
285 delegation->inode = NULL;
286 rcu_assign_pointer(nfsi->delegation, NULL);
287 spin_unlock(&delegation->lock);
288 return delegation;
289}
290
291static struct nfs_delegation *nfs_detach_delegation(struct nfs_inode *nfsi,
292 struct nfs_delegation *delegation,
293 struct nfs_server *server)
294{
295 struct nfs_client *clp = server->nfs_client;
296
297 spin_lock(&clp->cl_lock);
298 delegation = nfs_detach_delegation_locked(nfsi, delegation, clp);
299 spin_unlock(&clp->cl_lock);
300 return delegation;
301}
302
303static struct nfs_delegation *
304nfs_inode_detach_delegation(struct inode *inode)
305{
306 struct nfs_inode *nfsi = NFS_I(inode);
307 struct nfs_server *server = NFS_SERVER(inode);
308 struct nfs_delegation *delegation;
309
310 delegation = nfs_start_delegation_return(nfsi);
311 if (delegation == NULL)
312 return NULL;
313 return nfs_detach_delegation(nfsi, delegation, server);
314}
315
316static void
317nfs_update_inplace_delegation(struct nfs_delegation *delegation,
318 const struct nfs_delegation *update)
319{
320 if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) {
321 delegation->stateid.seqid = update->stateid.seqid;
322 smp_wmb();
323 delegation->type = update->type;
324 }
325}
326
327/**
328 * nfs_inode_set_delegation - set up a delegation on an inode
329 * @inode: inode to which delegation applies
330 * @cred: cred to use for subsequent delegation processing
331 * @res: new delegation state from server
332 *
333 * Returns zero on success, or a negative errno value.
334 */
335int nfs_inode_set_delegation(struct inode *inode, struct rpc_cred *cred, struct nfs_openres *res)
336{
337 struct nfs_server *server = NFS_SERVER(inode);
338 struct nfs_client *clp = server->nfs_client;
339 struct nfs_inode *nfsi = NFS_I(inode);
340 struct nfs_delegation *delegation, *old_delegation;
341 struct nfs_delegation *freeme = NULL;
342 int status = 0;
343
344 delegation = kmalloc(sizeof(*delegation), GFP_NOFS);
345 if (delegation == NULL)
346 return -ENOMEM;
347 nfs4_stateid_copy(&delegation->stateid, &res->delegation);
348 delegation->type = res->delegation_type;
349 delegation->pagemod_limit = res->pagemod_limit;
350 delegation->change_attr = inode->i_version;
351 delegation->cred = get_rpccred(cred);
352 delegation->inode = inode;
353 delegation->flags = 1<<NFS_DELEGATION_REFERENCED;
354 spin_lock_init(&delegation->lock);
355
356 spin_lock(&clp->cl_lock);
357 old_delegation = rcu_dereference_protected(nfsi->delegation,
358 lockdep_is_held(&clp->cl_lock));
359 if (old_delegation != NULL) {
360 /* Is this an update of the existing delegation? */
361 if (nfs4_stateid_match_other(&old_delegation->stateid,
362 &delegation->stateid)) {
363 nfs_update_inplace_delegation(old_delegation,
364 delegation);
365 goto out;
366 }
367 /*
368 * Deal with broken servers that hand out two
369 * delegations for the same file.
370 * Allow for upgrades to a WRITE delegation, but
371 * nothing else.
372 */
373 dfprintk(FILE, "%s: server %s handed out "
374 "a duplicate delegation!\n",
375 __func__, clp->cl_hostname);
376 if (delegation->type == old_delegation->type ||
377 !(delegation->type & FMODE_WRITE)) {
378 freeme = delegation;
379 delegation = NULL;
380 goto out;
381 }
382 if (test_and_set_bit(NFS_DELEGATION_RETURNING,
383 &old_delegation->flags))
384 goto out;
385 freeme = nfs_detach_delegation_locked(nfsi,
386 old_delegation, clp);
387 if (freeme == NULL)
388 goto out;
389 }
390 list_add_tail_rcu(&delegation->super_list, &server->delegations);
391 rcu_assign_pointer(nfsi->delegation, delegation);
392 delegation = NULL;
393
394 trace_nfs4_set_delegation(inode, res->delegation_type);
395
396out:
397 spin_unlock(&clp->cl_lock);
398 if (delegation != NULL)
399 nfs_free_delegation(delegation);
400 if (freeme != NULL)
401 nfs_do_return_delegation(inode, freeme, 0);
402 return status;
403}
404
405/*
406 * Basic procedure for returning a delegation to the server
407 */
408static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation *delegation, int issync)
409{
410 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
411 struct nfs_inode *nfsi = NFS_I(inode);
412 int err = 0;
413
414 if (delegation == NULL)
415 return 0;
416 do {
417 if (test_bit(NFS_DELEGATION_REVOKED, &delegation->flags))
418 break;
419 err = nfs_delegation_claim_opens(inode, &delegation->stateid,
420 delegation->type);
421 if (!issync || err != -EAGAIN)
422 break;
423 /*
424 * Guard against state recovery
425 */
426 err = nfs4_wait_clnt_recover(clp);
427 } while (err == 0);
428
429 if (err) {
430 nfs_abort_delegation_return(delegation, clp);
431 goto out;
432 }
433 if (!nfs_detach_delegation(nfsi, delegation, NFS_SERVER(inode)))
434 goto out;
435
436 err = nfs_do_return_delegation(inode, delegation, issync);
437out:
438 return err;
439}
440
441static bool nfs_delegation_need_return(struct nfs_delegation *delegation)
442{
443 bool ret = false;
444
445 if (test_bit(NFS_DELEGATION_RETURNING, &delegation->flags))
446 goto out;
447 if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags))
448 ret = true;
449 if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) {
450 struct inode *inode;
451
452 spin_lock(&delegation->lock);
453 inode = delegation->inode;
454 if (inode && list_empty(&NFS_I(inode)->open_files))
455 ret = true;
456 spin_unlock(&delegation->lock);
457 }
458out:
459 return ret;
460}
461
462/**
463 * nfs_client_return_marked_delegations - return previously marked delegations
464 * @clp: nfs_client to process
465 *
466 * Note that this function is designed to be called by the state
467 * manager thread. For this reason, it cannot flush the dirty data,
468 * since that could deadlock in case of a state recovery error.
469 *
470 * Returns zero on success, or a negative errno value.
471 */
472int nfs_client_return_marked_delegations(struct nfs_client *clp)
473{
474 struct nfs_delegation *delegation;
475 struct nfs_server *server;
476 struct inode *inode;
477 int err = 0;
478
479restart:
480 rcu_read_lock();
481 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
482 list_for_each_entry_rcu(delegation, &server->delegations,
483 super_list) {
484 if (!nfs_delegation_need_return(delegation))
485 continue;
486 if (!nfs_sb_active(server->super))
487 continue;
488 inode = nfs_delegation_grab_inode(delegation);
489 if (inode == NULL) {
490 rcu_read_unlock();
491 nfs_sb_deactive(server->super);
492 goto restart;
493 }
494 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
495 rcu_read_unlock();
496
497 err = nfs_end_delegation_return(inode, delegation, 0);
498 iput(inode);
499 nfs_sb_deactive(server->super);
500 if (!err)
501 goto restart;
502 set_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state);
503 return err;
504 }
505 }
506 rcu_read_unlock();
507 return 0;
508}
509
510/**
511 * nfs_inode_return_delegation_noreclaim - return delegation, don't reclaim opens
512 * @inode: inode to process
513 *
514 * Does not protect against delegation reclaims, therefore really only safe
515 * to be called from nfs4_clear_inode().
516 */
517void nfs_inode_return_delegation_noreclaim(struct inode *inode)
518{
519 struct nfs_delegation *delegation;
520
521 delegation = nfs_inode_detach_delegation(inode);
522 if (delegation != NULL)
523 nfs_do_return_delegation(inode, delegation, 1);
524}
525
526/**
527 * nfs_inode_return_delegation - synchronously return a delegation
528 * @inode: inode to process
529 *
530 * This routine will always flush any dirty data to disk on the
531 * assumption that if we need to return the delegation, then
532 * we should stop caching.
533 *
534 * Returns zero on success, or a negative errno value.
535 */
536int nfs4_inode_return_delegation(struct inode *inode)
537{
538 struct nfs_inode *nfsi = NFS_I(inode);
539 struct nfs_delegation *delegation;
540 int err = 0;
541
542 nfs_wb_all(inode);
543 delegation = nfs_start_delegation_return(nfsi);
544 if (delegation != NULL)
545 err = nfs_end_delegation_return(inode, delegation, 1);
546 return err;
547}
548
549static void nfs_mark_return_if_closed_delegation(struct nfs_server *server,
550 struct nfs_delegation *delegation)
551{
552 set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags);
553 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
554}
555
556static void nfs_mark_return_delegation(struct nfs_server *server,
557 struct nfs_delegation *delegation)
558{
559 set_bit(NFS_DELEGATION_RETURN, &delegation->flags);
560 set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state);
561}
562
563static bool nfs_server_mark_return_all_delegations(struct nfs_server *server)
564{
565 struct nfs_delegation *delegation;
566 bool ret = false;
567
568 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
569 nfs_mark_return_delegation(server, delegation);
570 ret = true;
571 }
572 return ret;
573}
574
575static void nfs_client_mark_return_all_delegations(struct nfs_client *clp)
576{
577 struct nfs_server *server;
578
579 rcu_read_lock();
580 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
581 nfs_server_mark_return_all_delegations(server);
582 rcu_read_unlock();
583}
584
585static void nfs_delegation_run_state_manager(struct nfs_client *clp)
586{
587 if (test_bit(NFS4CLNT_DELEGRETURN, &clp->cl_state))
588 nfs4_schedule_state_manager(clp);
589}
590
591/**
592 * nfs_expire_all_delegations
593 * @clp: client to process
594 *
595 */
596void nfs_expire_all_delegations(struct nfs_client *clp)
597{
598 nfs_client_mark_return_all_delegations(clp);
599 nfs_delegation_run_state_manager(clp);
600}
601
602/**
603 * nfs_super_return_all_delegations - return delegations for one superblock
604 * @sb: sb to process
605 *
606 */
607void nfs_server_return_all_delegations(struct nfs_server *server)
608{
609 struct nfs_client *clp = server->nfs_client;
610 bool need_wait;
611
612 if (clp == NULL)
613 return;
614
615 rcu_read_lock();
616 need_wait = nfs_server_mark_return_all_delegations(server);
617 rcu_read_unlock();
618
619 if (need_wait) {
620 nfs4_schedule_state_manager(clp);
621 nfs4_wait_clnt_recover(clp);
622 }
623}
624
625static void nfs_mark_return_unused_delegation_types(struct nfs_server *server,
626 fmode_t flags)
627{
628 struct nfs_delegation *delegation;
629
630 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
631 if ((delegation->type == (FMODE_READ|FMODE_WRITE)) && !(flags & FMODE_WRITE))
632 continue;
633 if (delegation->type & flags)
634 nfs_mark_return_if_closed_delegation(server, delegation);
635 }
636}
637
638static void nfs_client_mark_return_unused_delegation_types(struct nfs_client *clp,
639 fmode_t flags)
640{
641 struct nfs_server *server;
642
643 rcu_read_lock();
644 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
645 nfs_mark_return_unused_delegation_types(server, flags);
646 rcu_read_unlock();
647}
648
649static void nfs_mark_delegation_revoked(struct nfs_server *server,
650 struct nfs_delegation *delegation)
651{
652 set_bit(NFS_DELEGATION_REVOKED, &delegation->flags);
653 delegation->stateid.type = NFS4_INVALID_STATEID_TYPE;
654 nfs_mark_return_delegation(server, delegation);
655}
656
657static bool nfs_revoke_delegation(struct inode *inode,
658 const nfs4_stateid *stateid)
659{
660 struct nfs_delegation *delegation;
661 nfs4_stateid tmp;
662 bool ret = false;
663
664 rcu_read_lock();
665 delegation = rcu_dereference(NFS_I(inode)->delegation);
666 if (delegation == NULL)
667 goto out;
668 if (stateid == NULL) {
669 nfs4_stateid_copy(&tmp, &delegation->stateid);
670 stateid = &tmp;
671 } else if (!nfs4_stateid_match(stateid, &delegation->stateid))
672 goto out;
673 nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation);
674 ret = true;
675out:
676 rcu_read_unlock();
677 if (ret)
678 nfs_inode_find_state_and_recover(inode, stateid);
679 return ret;
680}
681
682void nfs_remove_bad_delegation(struct inode *inode,
683 const nfs4_stateid *stateid)
684{
685 struct nfs_delegation *delegation;
686
687 if (!nfs_revoke_delegation(inode, stateid))
688 return;
689 delegation = nfs_inode_detach_delegation(inode);
690 if (delegation)
691 nfs_free_delegation(delegation);
692}
693EXPORT_SYMBOL_GPL(nfs_remove_bad_delegation);
694
695/**
696 * nfs_expire_unused_delegation_types
697 * @clp: client to process
698 * @flags: delegation types to expire
699 *
700 */
701void nfs_expire_unused_delegation_types(struct nfs_client *clp, fmode_t flags)
702{
703 nfs_client_mark_return_unused_delegation_types(clp, flags);
704 nfs_delegation_run_state_manager(clp);
705}
706
707static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server)
708{
709 struct nfs_delegation *delegation;
710
711 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
712 if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags))
713 continue;
714 nfs_mark_return_if_closed_delegation(server, delegation);
715 }
716}
717
718/**
719 * nfs_expire_unreferenced_delegations - Eliminate unused delegations
720 * @clp: nfs_client to process
721 *
722 */
723void nfs_expire_unreferenced_delegations(struct nfs_client *clp)
724{
725 struct nfs_server *server;
726
727 rcu_read_lock();
728 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
729 nfs_mark_return_unreferenced_delegations(server);
730 rcu_read_unlock();
731
732 nfs_delegation_run_state_manager(clp);
733}
734
735/**
736 * nfs_async_inode_return_delegation - asynchronously return a delegation
737 * @inode: inode to process
738 * @stateid: state ID information
739 *
740 * Returns zero on success, or a negative errno value.
741 */
742int nfs_async_inode_return_delegation(struct inode *inode,
743 const nfs4_stateid *stateid)
744{
745 struct nfs_server *server = NFS_SERVER(inode);
746 struct nfs_client *clp = server->nfs_client;
747 struct nfs_delegation *delegation;
748
749 rcu_read_lock();
750 delegation = rcu_dereference(NFS_I(inode)->delegation);
751 if (delegation == NULL)
752 goto out_enoent;
753 if (stateid != NULL &&
754 !clp->cl_mvops->match_stateid(&delegation->stateid, stateid))
755 goto out_enoent;
756 nfs_mark_return_delegation(server, delegation);
757 rcu_read_unlock();
758
759 nfs_delegation_run_state_manager(clp);
760 return 0;
761out_enoent:
762 rcu_read_unlock();
763 return -ENOENT;
764}
765
766static struct inode *
767nfs_delegation_find_inode_server(struct nfs_server *server,
768 const struct nfs_fh *fhandle)
769{
770 struct nfs_delegation *delegation;
771 struct inode *res = NULL;
772
773 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
774 spin_lock(&delegation->lock);
775 if (delegation->inode != NULL &&
776 nfs_compare_fh(fhandle, &NFS_I(delegation->inode)->fh) == 0) {
777 res = igrab(delegation->inode);
778 }
779 spin_unlock(&delegation->lock);
780 if (res != NULL)
781 break;
782 }
783 return res;
784}
785
786/**
787 * nfs_delegation_find_inode - retrieve the inode associated with a delegation
788 * @clp: client state handle
789 * @fhandle: filehandle from a delegation recall
790 *
791 * Returns pointer to inode matching "fhandle," or NULL if a matching inode
792 * cannot be found.
793 */
794struct inode *nfs_delegation_find_inode(struct nfs_client *clp,
795 const struct nfs_fh *fhandle)
796{
797 struct nfs_server *server;
798 struct inode *res = NULL;
799
800 rcu_read_lock();
801 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
802 res = nfs_delegation_find_inode_server(server, fhandle);
803 if (res != NULL)
804 break;
805 }
806 rcu_read_unlock();
807 return res;
808}
809
810static void nfs_delegation_mark_reclaim_server(struct nfs_server *server)
811{
812 struct nfs_delegation *delegation;
813
814 list_for_each_entry_rcu(delegation, &server->delegations, super_list) {
815 /*
816 * If the delegation may have been admin revoked, then we
817 * cannot reclaim it.
818 */
819 if (test_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags))
820 continue;
821 set_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
822 }
823}
824
825/**
826 * nfs_delegation_mark_reclaim - mark all delegations as needing to be reclaimed
827 * @clp: nfs_client to process
828 *
829 */
830void nfs_delegation_mark_reclaim(struct nfs_client *clp)
831{
832 struct nfs_server *server;
833
834 rcu_read_lock();
835 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
836 nfs_delegation_mark_reclaim_server(server);
837 rcu_read_unlock();
838}
839
840/**
841 * nfs_delegation_reap_unclaimed - reap unclaimed delegations after reboot recovery is done
842 * @clp: nfs_client to process
843 *
844 */
845void nfs_delegation_reap_unclaimed(struct nfs_client *clp)
846{
847 struct nfs_delegation *delegation;
848 struct nfs_server *server;
849 struct inode *inode;
850
851restart:
852 rcu_read_lock();
853 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
854 list_for_each_entry_rcu(delegation, &server->delegations,
855 super_list) {
856 if (test_bit(NFS_DELEGATION_RETURNING,
857 &delegation->flags))
858 continue;
859 if (test_bit(NFS_DELEGATION_NEED_RECLAIM,
860 &delegation->flags) == 0)
861 continue;
862 if (!nfs_sb_active(server->super))
863 continue;
864 inode = nfs_delegation_grab_inode(delegation);
865 if (inode == NULL) {
866 rcu_read_unlock();
867 nfs_sb_deactive(server->super);
868 goto restart;
869 }
870 delegation = nfs_start_delegation_return_locked(NFS_I(inode));
871 rcu_read_unlock();
872 if (delegation != NULL) {
873 delegation = nfs_detach_delegation(NFS_I(inode),
874 delegation, server);
875 if (delegation != NULL)
876 nfs_free_delegation(delegation);
877 }
878 iput(inode);
879 nfs_sb_deactive(server->super);
880 goto restart;
881 }
882 }
883 rcu_read_unlock();
884}
885
886static inline bool nfs4_server_rebooted(const struct nfs_client *clp)
887{
888 return (clp->cl_state & (BIT(NFS4CLNT_CHECK_LEASE) |
889 BIT(NFS4CLNT_LEASE_EXPIRED) |
890 BIT(NFS4CLNT_SESSION_RESET))) != 0;
891}
892
893static void nfs_mark_test_expired_delegation(struct nfs_server *server,
894 struct nfs_delegation *delegation)
895{
896 if (delegation->stateid.type == NFS4_INVALID_STATEID_TYPE)
897 return;
898 clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags);
899 set_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
900 set_bit(NFS4CLNT_DELEGATION_EXPIRED, &server->nfs_client->cl_state);
901}
902
903static void nfs_inode_mark_test_expired_delegation(struct nfs_server *server,
904 struct inode *inode)
905{
906 struct nfs_delegation *delegation;
907
908 rcu_read_lock();
909 delegation = rcu_dereference(NFS_I(inode)->delegation);
910 if (delegation)
911 nfs_mark_test_expired_delegation(server, delegation);
912 rcu_read_unlock();
913
914}
915
916static void nfs_delegation_mark_test_expired_server(struct nfs_server *server)
917{
918 struct nfs_delegation *delegation;
919
920 list_for_each_entry_rcu(delegation, &server->delegations, super_list)
921 nfs_mark_test_expired_delegation(server, delegation);
922}
923
924/**
925 * nfs_mark_test_expired_all_delegations - mark all delegations for testing
926 * @clp: nfs_client to process
927 *
928 * Iterates through all the delegations associated with this server and
929 * marks them as needing to be checked for validity.
930 */
931void nfs_mark_test_expired_all_delegations(struct nfs_client *clp)
932{
933 struct nfs_server *server;
934
935 rcu_read_lock();
936 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
937 nfs_delegation_mark_test_expired_server(server);
938 rcu_read_unlock();
939}
940
941/**
942 * nfs_reap_expired_delegations - reap expired delegations
943 * @clp: nfs_client to process
944 *
945 * Iterates through all the delegations associated with this server and
946 * checks if they have may have been revoked. This function is usually
947 * expected to be called in cases where the server may have lost its
948 * lease.
949 */
950void nfs_reap_expired_delegations(struct nfs_client *clp)
951{
952 const struct nfs4_minor_version_ops *ops = clp->cl_mvops;
953 struct nfs_delegation *delegation;
954 struct nfs_server *server;
955 struct inode *inode;
956 struct rpc_cred *cred;
957 nfs4_stateid stateid;
958
959restart:
960 rcu_read_lock();
961 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
962 list_for_each_entry_rcu(delegation, &server->delegations,
963 super_list) {
964 if (test_bit(NFS_DELEGATION_RETURNING,
965 &delegation->flags))
966 continue;
967 if (test_bit(NFS_DELEGATION_TEST_EXPIRED,
968 &delegation->flags) == 0)
969 continue;
970 if (!nfs_sb_active(server->super))
971 continue;
972 inode = nfs_delegation_grab_inode(delegation);
973 if (inode == NULL) {
974 rcu_read_unlock();
975 nfs_sb_deactive(server->super);
976 goto restart;
977 }
978 cred = get_rpccred_rcu(delegation->cred);
979 nfs4_stateid_copy(&stateid, &delegation->stateid);
980 clear_bit(NFS_DELEGATION_TEST_EXPIRED, &delegation->flags);
981 rcu_read_unlock();
982 if (cred != NULL &&
983 ops->test_and_free_expired(server, &stateid, cred) < 0) {
984 nfs_revoke_delegation(inode, &stateid);
985 nfs_inode_find_state_and_recover(inode, &stateid);
986 }
987 put_rpccred(cred);
988 if (nfs4_server_rebooted(clp)) {
989 nfs_inode_mark_test_expired_delegation(server,inode);
990 iput(inode);
991 nfs_sb_deactive(server->super);
992 return;
993 }
994 iput(inode);
995 nfs_sb_deactive(server->super);
996 goto restart;
997 }
998 }
999 rcu_read_unlock();
1000}
1001
1002void nfs_inode_find_delegation_state_and_recover(struct inode *inode,
1003 const nfs4_stateid *stateid)
1004{
1005 struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
1006 struct nfs_delegation *delegation;
1007 bool found = false;
1008
1009 rcu_read_lock();
1010 delegation = rcu_dereference(NFS_I(inode)->delegation);
1011 if (delegation &&
1012 nfs4_stateid_match_other(&delegation->stateid, stateid)) {
1013 nfs_mark_test_expired_delegation(NFS_SERVER(inode), delegation);
1014 found = true;
1015 }
1016 rcu_read_unlock();
1017 if (found)
1018 nfs4_schedule_state_manager(clp);
1019}
1020
1021/**
1022 * nfs_delegations_present - check for existence of delegations
1023 * @clp: client state handle
1024 *
1025 * Returns one if there are any nfs_delegation structures attached
1026 * to this nfs_client.
1027 */
1028int nfs_delegations_present(struct nfs_client *clp)
1029{
1030 struct nfs_server *server;
1031 int ret = 0;
1032
1033 rcu_read_lock();
1034 list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link)
1035 if (!list_empty(&server->delegations)) {
1036 ret = 1;
1037 break;
1038 }
1039 rcu_read_unlock();
1040 return ret;
1041}
1042
1043/**
1044 * nfs4_copy_delegation_stateid - Copy inode's state ID information
1045 * @inode: inode to check
1046 * @flags: delegation type requirement
1047 * @dst: stateid data structure to fill in
1048 * @cred: optional argument to retrieve credential
1049 *
1050 * Returns "true" and fills in "dst->data" * if inode had a delegation,
1051 * otherwise "false" is returned.
1052 */
1053bool nfs4_copy_delegation_stateid(struct inode *inode, fmode_t flags,
1054 nfs4_stateid *dst, struct rpc_cred **cred)
1055{
1056 struct nfs_inode *nfsi = NFS_I(inode);
1057 struct nfs_delegation *delegation;
1058 bool ret;
1059
1060 flags &= FMODE_READ|FMODE_WRITE;
1061 rcu_read_lock();
1062 delegation = rcu_dereference(nfsi->delegation);
1063 ret = nfs4_is_valid_delegation(delegation, flags);
1064 if (ret) {
1065 nfs4_stateid_copy(dst, &delegation->stateid);
1066 nfs_mark_delegation_referenced(delegation);
1067 if (cred)
1068 *cred = get_rpccred(delegation->cred);
1069 }
1070 rcu_read_unlock();
1071 return ret;
1072}
1073
1074/**
1075 * nfs4_delegation_flush_on_close - Check if we must flush file on close
1076 * @inode: inode to check
1077 *
1078 * This function checks the number of outstanding writes to the file
1079 * against the delegation 'space_limit' field to see if
1080 * the spec requires us to flush the file on close.
1081 */
1082bool nfs4_delegation_flush_on_close(const struct inode *inode)
1083{
1084 struct nfs_inode *nfsi = NFS_I(inode);
1085 struct nfs_delegation *delegation;
1086 bool ret = true;
1087
1088 rcu_read_lock();
1089 delegation = rcu_dereference(nfsi->delegation);
1090 if (delegation == NULL || !(delegation->type & FMODE_WRITE))
1091 goto out;
1092 if (nfsi->nrequests < delegation->pagemod_limit)
1093 ret = false;
1094out:
1095 rcu_read_unlock();
1096 return ret;
1097}